0d94caffca
much higher filesystem I/O performance, and much better paging performance. It represents the culmination of over 6 months of R&D. The majority of the merged VM/cache work is by John Dyson. The following highlights the most significant changes. Additionally, there are (mostly minor) changes to the various filesystem modules (nfs, msdosfs, etc) to support the new VM/buffer scheme. vfs_bio.c: Significant rewrite of most of vfs_bio to support the merged VM buffer cache scheme. The scheme is almost fully compatible with the old filesystem interface. Significant improvement in the number of opportunities for write clustering. vfs_cluster.c, vfs_subr.c Upgrade and performance enhancements in vfs layer code to support merged VM/buffer cache. Fixup of vfs_cluster to eliminate the bogus pagemove stuff. vm_object.c: Yet more improvements in the collapse code. Elimination of some windows that can cause list corruption. vm_pageout.c: Fixed it, it really works better now. Somehow in 2.0, some "enhancements" broke the code. This code has been reworked from the ground-up. vm_fault.c, vm_page.c, pmap.c, vm_object.c Support for small-block filesystems with merged VM/buffer cache scheme. pmap.c vm_map.c Dynamic kernel VM size, now we dont have to pre-allocate excessive numbers of kernel PTs. vm_glue.c Much simpler and more effective swapping code. No more gratuitous swapping. proc.h Fixed the problem that the p_lock flag was not being cleared on a fork. swap_pager.c, vnode_pager.c Removal of old vfs_bio cruft to support the past pseudo-coherency. Now the code doesn't need it anymore. machdep.c Changes to better support the parameter values for the merged VM/buffer cache scheme. machdep.c, kern_exec.c, vm_glue.c Implemented a seperate submap for temporary exec string space and another one to contain process upages. This eliminates all map fragmentation problems that previously existed. ffs_inode.c, ufs_inode.c, ufs_readwrite.c Changes for merged VM/buffer cache. Add "bypass" support for sneaking in on busy buffers. Submitted by: John Dyson and David Greenman
249 lines
7.9 KiB
C
249 lines
7.9 KiB
C
/*
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* Copyright (c) 1991 Regents of the University of California.
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* All rights reserved.
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*
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* This code is derived from software contributed to Berkeley by
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* the Systems Programming Group of the University of Utah Computer
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* Science Department and William Jolitz of UUNET Technologies Inc.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* Derived from hp300 version by Mike Hibler, this version by William
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* Jolitz uses a recursive map [a pde points to the page directory] to
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* map the page tables using the pagetables themselves. This is done to
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* reduce the impact on kernel virtual memory for lots of sparse address
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* space, and to reduce the cost of memory to each process.
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*
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* from: hp300: @(#)pmap.h 7.2 (Berkeley) 12/16/90
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* from: @(#)pmap.h 7.4 (Berkeley) 5/12/91
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* $Id: pmap.h,v 1.19 1994/12/18 03:11:46 davidg Exp $
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*/
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#ifndef _MACHINE_PMAP_H_
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#define _MACHINE_PMAP_H_
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#include <machine/pte.h>
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typedef unsigned int *pd_entry_t;
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typedef unsigned int *pt_entry_t;
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/*
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* NKPDE controls the virtual space of the kernel, what ever is left, minus
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* the alternate page table area is given to the user (NUPDE)
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*/
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/*
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* NKPDE controls the virtual space of the kernel, what ever is left is
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* given to the user (NUPDE)
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*/
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#ifndef NKPT
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#if 0
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#define NKPT 26 /* actual number of kernel page tables */
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#else
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#define NKPT 9 /* actual number of kernel page tables */
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#endif
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#endif
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#ifndef NKPDE
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#define NKPDE 63 /* addressable number of page tables/pde's */
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#endif
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#define NUPDE (NPTEPG-NKPDE) /* number of user pde's */
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/*
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* The *PTDI values control the layout of virtual memory
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*
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* XXX This works for now, but I am not real happy with it, I'll fix it
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* right after I fix locore.s and the magic 28K hole
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*/
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#define APTDPTDI (NPTEPG-1) /* alt ptd entry that points to APTD */
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#define KPTDI (APTDPTDI-NKPDE)/* start of kernel virtual pde's */
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#define PTDPTDI (KPTDI-1) /* ptd entry that points to ptd! */
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#define KSTKPTDI (PTDPTDI-1) /* ptd entry for u./kernel&user stack */
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#define KSTKPTEOFF (NBPG/sizeof(pd_entry_t)-UPAGES) /* pte entry for kernel stack */
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#define PDESIZE sizeof(pd_entry_t) /* for assembly files */
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#define PTESIZE sizeof(pt_entry_t) /* for assembly files */
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/*
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* Address of current and alternate address space page table maps
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* and directories.
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*/
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#ifdef KERNEL
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extern pt_entry_t PTmap[], APTmap[], Upte;
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extern pd_entry_t PTD[], APTD[], PTDpde, APTDpde, Upde;
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extern int IdlePTD; /* physical address of "Idle" state directory */
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#endif
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/*
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* virtual address to page table entry and
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* to physical address. Likewise for alternate address space.
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* Note: these work recursively, thus vtopte of a pte will give
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* the corresponding pde that in turn maps it.
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*/
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#define vtopte(va) (PTmap + i386_btop(va))
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#define kvtopte(va) vtopte(va)
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#define ptetov(pt) (i386_ptob(pt - PTmap))
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#define vtophys(va) (((int) (*vtopte(va))&PG_FRAME) | ((int)(va) & PGOFSET))
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#define ispt(va) ((va) >= UPT_MIN_ADDRESS && (va) <= KPT_MAX_ADDRESS)
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#define avtopte(va) (APTmap + i386_btop(va))
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#define ptetoav(pt) (i386_ptob(pt - APTmap))
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#define avtophys(va) (((int) (*avtopte(va))&PG_FRAME) | ((int)(va) & PGOFSET))
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#ifdef KERNEL
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/*
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* Routine: pmap_kextract
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* Function:
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* Extract the physical page address associated
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* kernel virtual address.
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*/
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static __inline vm_offset_t
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pmap_kextract(vm_offset_t va)
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{
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vm_offset_t pa = *(int *)vtopte(va);
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pa = (pa & PG_FRAME) | (va & ~PG_FRAME);
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return pa;
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}
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/*
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* pmap_is_referenced:
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*
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* Return whether or not the specified physical page was referenced
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* by any physical maps.
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*/
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#define pmap_is_referenced(pa) pmap_testbit((pa), PG_U)
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/*
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* pmap_is_modified:
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*
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* Return whether or not the specified physical page was modified
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* in any physical maps.
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*/
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#define pmap_is_modified(pa) pmap_testbit((pa), PG_M)
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/*
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* Clear the modify bits on the specified physical page.
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*/
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#define pmap_clear_modify(pa) pmap_changebit((pa), PG_M, FALSE)
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/*
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* pmap_clear_reference:
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*
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* Clear the reference bit on the specified physical page.
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*/
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#define pmap_clear_reference(pa) pmap_changebit((pa), PG_U, FALSE)
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/*
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* Routine: pmap_copy_on_write
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* Function:
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* Remove write privileges from all
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* physical maps for this physical page.
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*/
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#define pmap_copy_on_write(pa) pmap_changebit((pa), PG_RW, FALSE)
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#endif
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/*
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* macros to generate page directory/table indicies
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*/
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#define pdei(va) (((va)&PD_MASK)>>PD_SHIFT)
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#define ptei(va) (((va)&PT_MASK)>>PG_SHIFT)
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/*
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* Pmap stuff
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*/
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struct pmap {
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pd_entry_t *pm_pdir; /* KVA of page directory */
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boolean_t pm_pdchanged; /* pdir changed */
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short pm_dref; /* page directory ref count */
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short pm_count; /* pmap reference count */
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simple_lock_data_t pm_lock; /* lock on pmap */
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struct pmap_statistics pm_stats; /* pmap statistics */
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long pm_ptpages; /* more stats: PT pages */
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};
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typedef struct pmap *pmap_t;
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#ifdef KERNEL
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extern pmap_t kernel_pmap;
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#endif
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/*
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* Macros for speed
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*/
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#define PMAP_ACTIVATE(pmapp, pcbp) \
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if ((pmapp) != NULL /*&& (pmapp)->pm_pdchanged */) { \
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(pcbp)->pcb_cr3 = \
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pmap_extract(kernel_pmap, (vm_offset_t)(pmapp)->pm_pdir); \
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if ((pmapp) == &curproc->p_vmspace->vm_pmap) \
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load_cr3((pcbp)->pcb_cr3); \
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(pmapp)->pm_pdchanged = FALSE; \
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}
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#define PMAP_DEACTIVATE(pmapp, pcbp)
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/*
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* For each vm_page_t, there is a list of all currently valid virtual
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* mappings of that page. An entry is a pv_entry_t, the list is pv_table.
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*/
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typedef struct pv_entry {
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struct pv_entry *pv_next; /* next pv_entry */
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pmap_t pv_pmap; /* pmap where mapping lies */
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vm_offset_t pv_va; /* virtual address for mapping */
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} *pv_entry_t;
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#define PV_ENTRY_NULL ((pv_entry_t) 0)
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#define PV_CI 0x01 /* all entries must be cache inhibited */
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#define PV_PTPAGE 0x02 /* entry maps a page table page */
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#ifdef KERNEL
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pv_entry_t pv_table; /* array of entries, one per page */
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#define pa_index(pa) atop(pa - vm_first_phys)
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#define pa_to_pvh(pa) (&pv_table[pa_index(pa)])
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#define pmap_resident_count(pmap) ((pmap)->pm_stats.resident_count)
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struct pcb;
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void pmap_activate __P((pmap_t, struct pcb *));
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void pmap_changebit __P((vm_offset_t, int, boolean_t));
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pmap_t pmap_kernel __P((void));
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boolean_t pmap_page_exists __P((pmap_t, vm_offset_t));
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pt_entry_t *pmap_pte(pmap_t, vm_offset_t);
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vm_page_t pmap_pte_vm_page __P((pmap_t, vm_offset_t));
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#endif /* KERNEL */
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#endif /* !_MACHINE_PMAP_H_ */
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